Ribbon cable and switch improvements in coupling means



June 20, 1967 w, M0RR|$ 3,327,077

RIBBON CABLE AND SWITCH IMPROVEMENTS IN COUPLING MEANS Filed NOV 2",1964 2 Sheets-Sheet 1 FIG. 2.

UCIEIEIEIUEICI EIEIEIL'JEIEIEID INVENTOR. ROBERT W. MORRIS June 20, 1967R. w. MORRIS 3,327,077

RIBBON CABLE AND SWITCH IMPROVEMENTS IN COUPLING MEANS Filed NOV.27,1964 2 Sheets-Sheet Fla 7 INVENTOR.

ROBERT W. MORRIS United States Patent 3,327,077 RIBBON CABLE AND SWITCHIMPROVEMENTS IN COUPLING MEANS Robert W. Morris, Webster, N.Y., assignorto Taylor Instrument Companies, Rochester, N.Y., a corporation of NewYork Filed Nov. 27, 1964, Ser. No. 414,192 Claims. (Cl. 200-51) Thisinvention relates to multi-wire connectors or couplings for electricalapparatus, wherein electrical devices of one sort and another areinterconnected in order to transfer electrical signal and power from oneto another,

whereby, as a result, it is expedient to provide mechanical and/ orelectrical interlock features, to manifold contacts, conductors and thelike, and to provide electrical isolation between power and signal.

The general object of the invention is to provide novel means embodyingthe aforesaid expedients. Specific, related objects of the inventionwill be apparent from the written description and claims, hereinbelow.

In the drawings, FIGURE 1 is an elevation of a separable coupling devicein accordance with the'invention, the FIGURE being partly in section onlines A-A of FIGURE 2, and on line BB.

FIGURES 2 and 3 are a plan view of parts of FIGURE 1, and FIGURE 4 is anenlarged detail of FIGURE 3.

FIGURES 5 and 6 illustrate a ribbon conductor or cable according to theinvention, and FIGURE 7 illustrates a support arrangement for suchribbon conductor or cable.

In FIGURE 1, the reference numeral 1 denotes a plate 1 and a plate-likeobject 2, the latter being shown broken at its upper end (see FIGURE 3)to signify that it might be a printed circuit board or the likecombining the general function of plate 1, i.e., to provide a deck ofcontacts that are adapted to interengage with the deck of contactsprovided by plate 1. Thus, plate 1 provides a plurality of connectors 3,each having a part 3a and a part 3b, the former providing for connectionto contact prongs on object 2 and the latter providing for connection tosignal wires or conductors 4 and power wires or conductors 5. The saidprongs are indicated at 6, one being shown in dotted line as projectingfrom object 2 into one of parts 3a. Parts 3a, 3b and prongs 4 areconventional electrical hardware, the said parts being of the typehaving a forcefit with each other and projecting through square orotherwise shaped holes 7 in plate 1 (see FIGURE 2). Other forms ofbayonet type interengaging contacts could of course be used.

It will be noted that, as indicated in FIGURE 3, there are two sets ofprongs 6 on object 2, so that plate 1 only requires 6 connectors 3. Asshown in FIGURE 2, however, there are two separate sets of holes 7, eachgreater in number than 3, thus providing for additional numbers ofconnectors. The two sets of holes 7 are relatively widely spaced, thusproviding for good electrical isolation between the two sets, therebeing suflicient spacing thus provided between the ends of conductorgroups 4 and 5 as to fulfill the common requirement (of electricalcodes, and the'like) for intrinsic safety.

Since prongs 6 and the female elements (not shown) of connectors 3necessarily interengage tightly enough to assure electrical contacttherebetween with very low contact resistance, such interengagement,when there are relatively large numbers of connectors and prongs,provides substantial amounts of mechanical resistance to pull the plate1 away from object 2.

However, it is commonly desirable to provide a positive mechanicalinterlock between plate 1 and object 2, independent of the electricalconnections. Such mechanical readjust the position of knob 13 interlockis provided by the keyhole slot 8 in object 2, and flange 9. Flange 9 ismounted on a stud 10 passing through slot 8 and through a second slot 11in plate 1. Slots 8 and 11 are each parallel-sided, and the sides of theone slot are parallel to the sides of the other slot when plate 1 andobject 2 are in the engaged position shown in FIGURE 1. Slot 8, however,has an enlarged portion 12 of sufficient opening size to permit thepassage of flange 9 therethrough, whereas the width of the slots 8 and11 are otherwise just suflicient to pass the stud 10, so that byproviding relative proportions such as shown for slots, flange and stud,the flange overlaps the sides of the narrow portion of slot 8, in theillustrated position of the flange to such extent that the overlap willprevent pulling plate 1 from object 2 without exerting a force largeenough to damage the parts involved.

In the position shown in FIGURE 1 for plate 1 and object 2, parts 3awill have the same length, and the spacing of plate 1 and object 2 isfixed by the length of parts 3a. Stud 10 is provided at the end thereofopposite the end having flange 9 fixed thereon with a knob 13, said knobbeing secured to stud 10 by suitable means such as a set screw 14.

The spacing between the right-hand side of flange 9 and the left-handside of knob 13 may be made slightly less than the length of parts 3aplus the thickness of plate 1 and plate 2, so that the flange forcesplate 1 and object 2 together against the inherent resistance of theparts involved, some of which may be plastic, for example, the externalportions of parts 3a and/or one or the other of plate 1 and object 2 maybe made of a stiff fiber, plastic or laminate, such as is commonly usedin making circuit boards and the like. Stud 10 would consequently beretained securely in place (i.e., the position shown in FIGURE 1), as,for example, by the frictional forces between flange and knob, on theone hand, and the object 2 and plate 1, respectively, on the other hand.However, as shown, most or even all of said frictional forces aresupplied by means of a flat Teflon washer 13a, both washers beingmounted on stud 10 between the right-hand surface of plate 1 and theleft-hand surface of knob 13. The right-hand end of stud 10 is receivedin a well or hole of suflicient extent as to allow the knob 13 to beslipped to different positions along stud 10, and fixed in the desiredone of said positions by means of set screw 14. In this case, theposition of knob 13 on stud is chosen to be such as to flatten outWasher 13b against Washer 13a enough to generate a suitable amount offriction between the contacting surfaces of plate 1 and Teflon washer13a. In this way, flange 9 does not need to exert any frictionresistance to sliding rod 13 along slot 8, since all such resistance canbe provided in just the right degree by washer 13a against plate 1. Asboth plate 1 and object 2 would normally be more or less rigid, it isevident that the relatively considerable force pulling the plate 1 andobject 2 together enough to generate suflicient resistance by means offlange 9 and knob 13 (normally metallic objects), would be likely toscore, wear and otherwise mar the surfaces of plate 1 and object, sothat it would be necessary to periodically on stud 10 in order tomaintain enough frictional resistance to maintain knob 13, stud 10 andflange 9 in the right position along the length of the slot 8.

In order to create the necessary force on the washers 13a and 13b, theright-hand surface (looking from the point of view of FIGURE 1) of amagnet support 24 (considered more fully hereinafter) which is smoothand large enough to slip fairly readily over the surface of plate 1, isutilized. As carrier 24 is fixed to stud 10, it is between it and knob13 that the force compressing washer 13b is generated, rather thanbetween flange 9 surface on plate 1, the frictional force between washer13a and plate 1 can be adjusted over a substantial range by varying thedegree of compression of the corrugations of washer 13b.

2 In order to allow the plate 1 to be disengaged from abject 2, knob 13is grasped and pushed upwards to bring the flange over enlarged portion12 of slot 8, at which point the plate 1 can be pulled away from object2 merely by exerting enough force to overcome the collective frictionalresistance between prongs 6 and the parts 3a.

As connectors 3 and prongs 6 are normally not designed to providesubstantial mechanical support and stability for the interengaged plateand object, other than against the force exerted by stud 10 to holdplate 1 and object 2 together, pillars and 16 are provided, securelyfixed to one of object 2 and plate 1 (as shown to object 2). Saidpillars are of sufficient length and so-oriented that when interengagedwith corresponding holes in the other of plate 1 and object 2 (as shown,in plate 1) the plate 1 is substantially constrained to translationtoward object 2, and away from it as the case may be, whenever thespacing between the plate and object is small enough that prongs 6 beginto enter parts 3a. That is, pillars 15 and 16, and holes 17 and 18, wheninterengaged substantially prevent plate 1 from having components ofmotion parallel to the general plane of object 2. Prongs 6 and the parts3a are, of course, normal to this plane. Accordingly, the forces exertedon prongs 6 and connectors 3, due to pushing the knob up or down, isslight or non-existent, dependent on the play that holes 17 and 18 allowin the vertical direction when plate 1 is parallel to object 2. As aresult, the connectors 3 and prongs 6 are maintained in proper alignment(for their interengagement) by means of pillars 15 and 16, and holes 17and 18. The pillars 15 and 16 are long enough that such alignment isestablished prior to the point at which prongs 6 begin to enterconnectors 3.

As shown, the pillars 15 and 16 may be of uniform cross-section but ofdifferent cross-sectional shapes, and holes 17 and 18 arecorrespondingly shaped, thus keying the plate and object together insuch a way as to prevent interengagement of the wrong sets or pair ofprongs 6 and parts 3a. While in the location shown, the keyhole slot 8also has a keying efifect, prongs 6 and parts 3a are commonlysufficiently long that electrical interengagement thereof may beginwhile the left side of flange 9 is still spaced from the right side ofobject 2. Moreover, where the enlarged ortion 12 centered betweenpillars 15 and 16, there would be no keying effect preventinginterengagement of the wrong prongs and parts 3a. While hole 18 wouldnormally be termed a notch, a notch is merely a hole with a portion ofits periphery missing, and it is merely a matter of routine choice as towhether what is used is actually a notch or is actually a hole, in theconventional senses of these terms.

The assembly of FIGURE 1 also includes an electrical interlockcomprising a magnetic reed proximity switch 19 of conventional type, anda permanent magnet 20 for opening and closing the contacts 21 of theswitch, thus making and breaking the conductive path between a pair ofterminals 22 and 23 of the switch, which terminals are secured to object2.

The mechanical locking action of the rod 10 is used to open and closecontacts 21. Thus, a support 24 is rigidly carried by the stud 10, andthe magnet 20 is secured in said support, the seat being so located onstud 10 that when the plate 1 and object 2 are engaged as shown inFIGURE 1, the magnet 20 is directly over switch 19. As will be seen fromthe magnified view of FIGURE 4, the full-line showing of magnet 20indicates the orientation of magnet 20 when the rod 10 is 4 positionedas shown in FIGURE 1. Dotted line representation 20 indicates theposition of magnet 20 that will be obtained if knob 13 is pushed upward(in the view of FIGURE 1) so as to position flange 9 directly over hole12 so as to permit next the plate 1 to be translated away from magnet 2.

In one of the two above-described positions of magnet 20, the contactswill be open and the contacts between prongs 6 and parts 3a beinginterengaged at that time as illustrated in FIGURE 1. In the other ofsaid above-dc scribed positions, such interengagement of contacts willstill be as illustrated in FIGURE 1, but now the contacts 21 will beclosed. In this case, it is desired that the contracts open preparatoryto removing plate 1 from object 2, whereas the contacts close when theplate 1, after having been disengaged from object 2, is engagedtherewith, but not until knob 13 has been pushed down (in the view ofFIGURE 1) to mechanically lock the plate 1 and object 2 together.However, it is obvious that the reverse situation could be provided, asto contact opening and closing, without departing from the invention.

As shown in FIGURE 1, the sets of conductors 3 and 4 are manifolded, notonly by the connectors 3 on plate 1, but also by being incorporated in aribbon cable 25. Ribbon cable 25 comprises mainly a ribbon of plastichaving wires embedded therein parallel to each other and to the sides ofthe ribbon of plastic which is of substantially uniform width andthickness. As shown, the ribbon conductor is made up of tubular elementssuch as shown at 26, some of which form tubular insulating elements forwires, some of which are shown at 27, and some of which have no wirestherein and are either simply plastic tubes or solid plastic strands. Inpractice, the tubular elements are bonded together or integrallyconnected at their sides to form the overall ribbon cable 25.

It will be observed that the two groups of conductors 4 and 5 areseparated one from another by a substantial expanse of ribbon, in whichexpanse conveniently, for the most part at least, no wires 27 arelocated. It will be noted,

however, that certain oftubular elements 26 next adjacent or actually inthe groups 3 and 4 are cut short just as are the tubular elementsbetween the groups even though the former said elements contain wires27.

In order that twisting the ribbon cable 25 will not result in groups 3and 4 from crossing over each other at a distance much less than that ofthe width of ribbon separating them in the cable 25, splints 28 areprovided made of material that is relatively stiff compared to theribbon,

' thereby reducing the likelihood of the cable 25 being folded bytwisting it. -In order to provide a certain amount of leeway in fittingthe ribbon to the plate, other splints 29 may be provided at the end ofthe ribbon of such sort as to allow some folding of the ribbon toaccommodate the width of the ribbon to the spacing of the groups ofconductors 3 and 4, by providing an unsplinted portion of ribbonbet-ween the two inner ends of the splints 29, which otherwise extendacross the whole width of the ribbon,

and are cemented or otherwise securely bonded along their lengths to thenext adjacent surfaces of the ribbon. Generally speaking, however, it ispreferable to use splints 28 whenever possible, because each of splints28 is substantially as wide as the ribbon, and is affixed thereto bycernenting or the like, all along its length, to the next adjacentsurface of the ribbon, thereby preventing substantially any bending ofcable 25, except around a splint. Splints 28 and 29 may be hollowplastic tubes, or the like, although as shown a splint 28 is a hollowtube 30 having a solid core 31, the former being of a nature suitablefor fixing it to the strip (which in the case of suitable plastics oftenleaves something to be desired in the way of rigidity and/or strength)whereas the core supplies rigidity and strength. The splints 28 and 29in any event should be of material having insulating properties, inorder to avoid coupling the conductors 3 to the conductors 4.

As is evident from FIGURE 5, ribbon cable 25 is accordion-folded toprovide folds several of which are shown at 32. Splints 28 (and 29) arelocated within the folds 32, so that sections of ribbon cable are bentaround the splints, said splints thus preventing the folds from beingcreased to such extent as to weaken the ribbon material, and/ or wire atthe location of the folds. That is, the splints pre vent the ribbonmaterial and/ or wire from being bent to a radius small enough todistort the 'wire and/or ribbon material to the point of weakening orbreaking it.

In FIGURE 7, a slight modification of the splint 28 provides anadditional means for isolating the conductors in the cable. The core 31of the splint is conveniently made from a plastic such as nylon orTeflon, which is durable, strong and relatively rigid. Hence, byprolonging the core 31 at either end, beyond the margins of the table,extensions 31a are provided such as permit supporting a fold 32 of cable25 on the cars 34 of a bracket 33 or the like, suitable holes orequivalent being provided in the cars 34, receiving extensions 31a. Thisfeature is particularly useful for supporting an end of the cableterminating in close proximity to a chassis, casing or like object, asthe ears 31a will hold the cable end off such object. Moreover, thebracket 33 provides an anchorage for the cable, independently of theelectrical connections terminating the wires at the cable end, as forexample, in FIGURE 1 where insofar as the illustration goes, connectors3 provide the sole support for, hence, it would be often advantageous toprovide a braket corresponding to bracket 33, but fixed to plate 1 sothat the cable end is primarily supported in effect by plate directly,rather than by the connectors 3. The form of bracket shown is but one ofmany that might be used, as will be obvious to one skilled in the art.Bracket 33 will normally be constructed for assembly and disassembly ofthe cable splint, as by having a flexible, removable or slotted car 34.For purposes of illustration, bracket 34 is shown as mounted on achassis-like object 50, however, it is obvious that the object 50 couldhave ears formed integrally thereon rather than as part of a nominallydistinct element such as the bracket 33.

The invention as described thus far is useful generally as means forelectrical coupling items of electrical apparatus together. One use ofthis sort is in coupling together the components ofelectronic processcontrol systems such as are disclosed in US. Patent No. 3,069,554 to R.M. Decker et al., issued December 18, 1962, and assigned to the assigneeof the present invention. It will be observed from FIGURE 2 of saidpatent that such a system involves numerous occasions for manifoldingconductors together either as a ribbon cable and/or at a common terminalstrip, circuit board, chassis, or the like, while maintaining aconsiderable degree of electrical isolation between groups ofconductors, connections, etc.

Such isolation is provided by the invention herein, as may be seen fromthe positions of the two groups of prongs 6 on object 2 (see FIGURE 3),from the separation in ribbon cable 25 between conductors 3 andconductors 4, and from the positions of the two groups of mounting holes7 in plate 1 (FIGURE 2). As will be seen from FIGURE 2, also, thepresence of stud 10, flange 9, knob 13, carrier 24 and magnet 20', whichin practice amount in effect to a single conductive element in that eachpart thereof is normally made of metal, does not introduce a significantamount of coupling between conductors 3 and conductors 4, or between thecorre sponding groups of elements forming connections of these on object2 and plate 1.

In a system of the kind in question, one of the groups 3 and 4 willinclude conductors supplying electrical power to operate a device suchas an amplifier, of which the object 2 may form part. It is thendesirable, when disconnecting the ribbon cable 25, to first cut olf thepower. Consequently, the switch 20 may form part of the electrical powercircuit, so that when contacts 21 open, power in the electrical circuitassociated with object 2, is cut off.

The other of groups 3 and 4 would include conductors for connectingvarious signals to the aforesaid electric circuit, say, as an input orinputs to an amplifier, and so on, and of such nature that if locatedtoo closely to a power conductor, electrostatic coupling due to theproximity of signal and power conductors can couple undesired electricaldisturbances from the power conductors to the signal conductors. Thecoupling according to the invention obviously prevents suchelectrostatic coupling.

It may also be desired to house the structure including object 2 in acasing, rack, or the like, and to provide for its withdrawal from suchcasing, rack, or the like, without disturbing the connection of theribbon cable 25 to some other entity, at its end, opposite the oneconnected to plate 1. The accordion folding of the cable 25 allows suchwithdrawal to be made, while permitting the cable to fold up,accordion-style, in a relatively small space when the said structure isreplaced. Splinting the cable assists in maintaining the accordion formof cable 22 free of folds and twists that might otherwise bring powerand signal wires in close proximity and strengthens the folds, andsimultaneously provides strength for the cable at the folds 32.

It is also obvious that object 2 might be a plate quite similar to plate1, and that the cable 25 might terminate with a second plate havingconnections thereon like plate 1, with an object like object 2. As theart is replete with varied sorts of electrical systems, apparatus, andthe like, having units or sections thereof coupled together by means ofseparable coupling providing contacts manifolded on plate-like elements,it is unnecessary to further indicate here the use and application ofthe present invention. Likewise, those skilled in the art will be awareof numerous practical modifications and/or substitutions in respect todetail such as the interengaging contact structure provided by prongs 6and connectors 3, and the like, without departing from the inventionherein. Accordingly, the scope of my invention is to be ascertained fromthe claims appended hereto, rather than from the detailed descriptionhereof.

I claim:

1. In combination, coupling means and an object, said coupling meanscomprising a plate having a plurality of conductor connections thereonand said object having a plurality of conductor connectionscorresponding to the said conductor connections on said plate, andconductively engaged therewith; a magnet, said plate having meansmounting said magnet thereon for movement of said magnet between firstand second given positions on said plate, both in proximity to saidobject; said object having a magnetically-actuatable switch positionedthereon next the path of movement of said magnet and such that if saidmagnet is moved to said first given position, said switch is actuatedthereby to a first state, whereas if said magnet is moved to said secondgiven position, said switch is actuated thereby to a second state, onesuch state being closed and the other such state being open.

2. The invention of claim 1, including mechanical looking elements, oneon said object, the other including said means mounting said magnet andmovable bodily there with, said elements being so constructed andarranged that in one of said given positions said elements areinterlocked in such fashion as to prevent said plate and said objectfrom being pulled apart, whereas in the other of said positions, saidelements are free, one from the other, such as to allow said plate to bepulled away from said object.

3. In combination with coupling means having a group of connections, theimprovement comprising a multi-conductor-type ribbon cable, said ribboncable consisting essentially of a ribbon of insulating material havingconductors embedded therein and said conductors being connected tocertain of said connections, said ribbon having splints fixed thereto,said splints being rigid in comparison to said ribbon, said splintslying transverse to the consisting essentially of a ribbon of insulatingmaterial having both said plural conductor means embedded therein sideby side and the intermediate portion of said ribbon between the inmostof said first conductor means and the inmost of said second conductormeans being large in width compared to the spacing between next-adjacentfirst conductor means and the spacing between next-adjacent secondconductor means, said intermediate portion being free of conductormeans, and said ribbon cable having splints fixed thereto, said splintsbeing rigid in comparison to said ribbon, said splints lying transverseto the length of said ribbon and across the width thereof, and saidsplints being spaced one from another alongsaid ribbon; said ri-b'bonbeing accordion-folded at spaced ones of said splints, each of said lastspaced ones of said splints being located at a fold and between thesections of ribbon next-adjacent such fold.

5. The invention of claim 4, wherein one of said splints has extensionson either side of said ribbon, there being a bracket means having earmeans supporting said extensions, and said bracket means being fixed toan object to which said conductor means are connected.

References Cited UNITED STATES PATENTS 2,710,384 6/1955 Dupre et a1.2,848,572 '8/ 1958 Wagnecz. 2,865,979 12/ 8 Klassen 174-69 2,902,5359/1959 Francis 174-69 3,004,235 10/ 1961 Cohen. 3,005,739 10/ 1961 Lang.3,005,885 10/ 1961 Bowditch et al ZOO-87 3,235,833 2/1966- Elm 174117.5

FOREIGN PATENTS 373,142 4/ 1963 Germany.

OTHER REFERENCES I. W. Jensen, Self-Retracting Cables for ElectronicEquipment, Hughes Aircraft Co., Culver City, Calif., 1958 (FIGURE 3,page 6 relied on).

ROBERT K. SCHAEFER, Primary Examiner.

K. H, CLAFFY, D. S. SMITH, Assistant Examiners.

1. IN COMBINATION, COUPLING MEANS AND AN OBJECT, SAID COUPLING MEANSCOMPRISING A PLATE HAVING A PLURALITY OF CONDUCTOR CONNECTIONS THEREONAND SAID OBJECT HAVING A PLURALITY OF CONDUCTOR CONNECTIONSCORRESPONDING TO THE SAID CONDUCTOR CONNECTIONS ON SAID PLATE, ANDCONDUCTIVELY ENGAGED THEREWITH; A MAGNET, SAID PLATE HAVING MEANSMOUNTING SAID MAGNET THEREON FOR MOVEMENT OF SAID MAGNET BETWEEN FIRSTAND SECOND GIVEN POSITIONS ON SAID PLATE, BOTH IN PROXIMITY TO SAIDOBJECT; SAID OBJECT HAVING A MAGNETICALLY-ACTUATABLE SWITCH POSITIONEDTHEREON NEXT THE PATH OF MOVEMENT OF SAID MAGNET AND SUCH THAT IF SAIDMAGNET IS MOVED TO SAID FIRST GIVEN POSITION, SAID SWITCH IS ACTUATEDTHEREBY TO A FIRST STATE, WHEREAS IF SAID MAGNET IS MOVED TO SAID SECONDGIVEN POSITION, SAID SWITCH IS ACTUATED THEREBY TO A SECOND STATE, ONESUCH STATE BEING CLOSED AND THE OTHER SUCH STATE BEING OPEN.